AddSwapFile

With ZFS

 zfs create -V 10gb zone/swap
 /usr/sbin/swap -a /dev/zvol/dsk/zone/swap

How to add swap via a file:

 /usr/sbin/mkfile 1024m /the/file/I/created
 /usr/sbin/swap -a /the/file/I/created

Use swap -l to verify that the swap file has been activated.